This invention relates to apparatus for optically measuring the width of a gap between two abutting panel surfaces as viewed down a fastener hole through which a bolt or rivet will be inserted to secure the panels, one to the other.
Optical displacement and contour measuring are known in the art. U.S. Pat. No. 4,411,528 to Newcomb, et al describes apparatus which projects a circular ring of light on a test surface. The diameter of the circular beam of light varies as a function of the distance of the test surface from an imaginary test surface. The center of the circle varies as a function of the obliquity between the test and reference surfaces.
Borescopes are also known in the art and are commonly used by industry for inspecting such things as aircraft engines and complex pressure vessels.
A manual gap measuring approach is also known in the prior art. Contact type "feeler" gages can be used, their function being to probe down through the previously drilled fastener holes, detect any gap and insert the tip of the gage. The correct thickness gage must be selected or a selection of gages built up to attain the best "contact" fit, rather like measuring spark plug gaps with a kit of feeler gages.
None of the prior art systems disclose a video-optical approach which measures gaps to close tolerances, is easy to set up and use, and provides computer storage of data.